Thermostat Busted!

engines

#1

Elementary car questions -



Engine overheating. Fluids okay. So, I took it in expecting a bad thermostat. Mechanic described the thermostate as busted. What could cause it to physically bust? Is that what happens when they fail?



I’m a little leary of anything a local mechanic says. I had a really bad experience since moving with a SAAB to a smallish Southern city where only 12 people drive SAABS and I bet I’m the only one with a 1991 model (only 95,000 miles and I’d like to drive another 17 years).



A simple check up (oil changes and coolant check) resulted in several visits to this other mechanic. A/C kept exploding within the 3 miles from dealership to my home. But they never accepted any responsibity! It was a new and different excuse everytime it happened. The last excuse before I switched mechanics was crushed fan.



How could the passenger side fan become cracked/busted. It still appeared to work with a little duct tape, though I’m having it replaced.



As you can tell, I’m very concerned that I was taken for a ride by the last mechanic. Today’s guy is probably great, and he’s just trying to correct the problems of the last guy. But I can’t help but be a bit skeptical.


#2

“Busted” may be just a case of semantics. Using that terminology he sounds like a knucklehead to me.

Most thermostats “fail,” such as “not open when it should.” Many thermostats will open between 160-195 degrees, allowing your car to cool. On american cars thermostats cost around five bucks and take minutes to install. The thermostat problem can in no way have anything to do with your other issues.

The other problems youre having require more information to determine the cause. I personally would first start with the Better Business bureau and check local court filings on these mechanics. Talk to anyone who may have sued them. They may even have criminal records! Then you can better decide who to stay away from. Good Luck!


#3

Thanks. Will contact BBB, et al

For further understanding, original mechanic said one fan for radiator only and second (crushed) fan only kicks in when the A/C is on. Today’s mechanic says engine needs second fan as an auxillary whether A/C is on or not. Since the passenger side (A/C?) fan was crushed I was not using the A/C. Been googling but can’t find this detailed an explanation for each of the fans.


#4

I have seen t~stats break. The cone stays in the housing but the pring and valve fall into the coolant passage in the block. This can as a result cause overheating do to the coolant circulating to fast. If the coolant does not stay in the radiator long enough it wont cool before being returned to the block.

As far as the fans are concerned: You have a primary engine cooling fan and a secondary A/C fan. If the temperature of the engine coolant gets hot enough the ECM will trigger the auxilary fan.


#5

Thanks all!

Historically, I have trusted my Saab mechanics who love my car almost as much as I do. But they have also respected me enough to answer my questions, even the stupid ones.

So thanks for taking the time to help me understand the second mechanic’s (who was recommended by a colleague) diagnosis.